Polyethylene (PE) crosslinking tshuab yog ib qho tseem ceeb ntawm kev txhim kho nws cov khoom siv. Kev hloov kho PE tuaj yeem txhim kho nws cov khoom zoo, uas tsis yog tsuas yog txhim kho cov khoom zoo ntawm PE xws li cov khoom siv kho tshuab, ib puag ncig kev nyuaj siab tawg, tshuaj tiv thaiv corrosion, creep resistance, thiab hluav taws xob zog, tab sis kuj tseem txhim kho qhov kub thiab txias. qib, uas tuaj yeem ua kom cov cua sov ua kom sov ntawm PE los ntawm 70 degree mus rau ntau tshaj 100 degree, yog li nthuav dav rau daim ntawv thov ntawm PE.
Hla-txuas polyethylene rwb thaiv tsev yog polyethylene nyob rau hauv qhov kev txiav txim ntawm high-zog rays (xws li rays, rays, electron rays, thiab lwm yam) los yog cross-linking agents kom cross-linking ntawm macromolecules tuaj yeem txhim kho nws cov cua sov thiab lwm yam khoom. Lub sij hawm ntev ua haujlwm kub ntawm lub cable siv cross-linked polyethylene li rwb thaiv tsev tuaj yeem nce mus rau 90 degree, thiab qhov kub ntawm lub voj voog luv luv uas tuaj yeem tiv taus tuaj yeem ncav cuag 170-250 degree .
Kev taw qhia luv luv
Polyethylene (PE) yog ib qho ntawm tsib cov khoom siv dav dav, thiab nws cov khoom siv thiab kev siv khoom yog thawj ntawm ntau yam khoom siv hluavtaws, hauv kev lag luam thiab kev ua liaj ua teb thiab siv dav hauv lub neej txhua hnub. Txawm li cas los xij, qhov kub-kub kuj ntawm polyethylene tsis zoo. Cov khoom siv kho tshuab thiab tshuaj lom neeg kuj qee zaum tsis ua raws li qhov yuav tsum tau ua ntawm kev siv tiag tiag. Yog li ntawd, kev hloov kho ntawm polyethylene ib txwm yog tus yuam sij rau kev txhim kho thiab siv cov khoom siv polyethylene, thiab polyethylene crosslinking tshuab yog ib qho tseem ceeb thev naus laus zis los txhim kho nws cov khoom siv. Hla-txuas hloov kho polyethylene tuaj yeem txhim kho nws cov khoom zoo, uas tsis tsuas yog txhim kho cov khoom zoo ntawm polyethylene xws li cov khoom siv kho tshuab, ib puag ncig kev ntxhov siab tawg tsis kam, tshuaj tiv thaiv corrosion, creep resistance, thiab hluav taws xob khoom. Tsis tas li ntawd, qhov ntsuas kub tsis kam tiv thaiv tau zoo heev, thiab qhov kub thiab txias ntawm polyethylene tuaj yeem nce los ntawm 70 degree mus rau ntau tshaj 100 degree. Yog li ntawd, kev siv ntau yam ntawm polyethylene tau nthuav dav heev.
Tam sim no, cross-linked polyethylene (XLPE) tau siv dav hauv cov kav dej, cov yeeb yaj kiab, cov ntaub ntawv cable, thiab cov khoom ua npuas ncauj.
Kev ua tau zoo thiab cov txiaj ntsig
Cov molecules ntawm polyethylene yog tsim los ntawm linear molecular chains. Thaum qhov kub thiab txias, qhov sib khi quab yuam ntawm cov kab hluav taws xob molecular chains (van der Waals quab yuam) tsis muaj zog, kom tag nrho cov khoom siv molecular deformed, yog li qhov kub tsis kam ntawm polyethylene tsis zoo. Hla-txuas polyethylene (XLPE) Ib qho tshuaj saw txuas txuas txuas ntawm cov molecules kom cov molecules tsis tuaj yeem hloov chaw, uas kov yeej qhov tsis txaus ntawm polyethylene. Kev sib piv ntawm kev sib txuas ntawm polyethylene thiab cov polyethylene zoo tib yam yog qhia hauv Table 1.
Hla-txuas polyethylene muaj cov hauv qab no zoo:
1. Thaum tshav kub kub kuj: XLPE nrog ib tug mesh peb-dimensional qauv muaj zoo heev kub kuj. Nws yuav tsis decompose thiab carbonize hauv qab 200 degree, lub sij hawm ntev ua hauj lwm kub yuav ncav cuag 90 degree, thiab lub thermal lub neej yuav ncav cuag 40 xyoo.
2. Rwb thaiv tsev kev ua tau zoo: XLPE tswj tus yam ntxwv zoo rwb thaiv tsev ntawm PE, thiab cov rwb thaiv tsev tiv thaiv tau nce ntxiv. Nws cov dielectric poob tangent yog me me thiab tsis cuam tshuam los ntawm qhov kub thiab txias.
3. Mechanical zog: Vim yog tsim cov tshuaj sib txuas tshiab ntawm macromolecules, hardness, txhav, hnav tsis kam, thiab kev cuam tshuam ntawm XLPE tau txhim kho, yog li ua rau qhov tsis zoo ntawm PE ua rau muaj kev ntxhov siab thiab tawg.
4. Tshuaj tiv thaiv: XLPE muaj zog acid thiab alkali tsis kam thiab roj tsis kam, thiab nws cov khoom combustion feem ntau yog dej thiab carbon dioxide, uas tsis tshua muaj teeb meem rau ib puag ncig thiab ua tau raws li cov kev cai ntawm kev nyab xeeb hluav taws niaj hnub no.
Crosslinking txoj cai
Polyethylene ([CH2-CH2]n, n-repeat unit naj npawb) yog ib qho khoom siv polymer uas muaj ob lub ntsiab lus ntawm hydrocarbons thiab hydrogens, nrog cov kab los yog cov ceg ntoo molecular qauv macromolecular chains, khoom hauv chav sov, thiab siv lead ua theem thiab amorphous theem coexistence daim ntawv nyob rau hauv cov khoom ntawm polyethylene. Tus txheeb ze molecular hnyav ntawm polyethylene yog nyob nruab nrab ntawm 6,30 thiab<>,<>.
Polyethylene muaj cov khoom siv hluav taws xob zoo heev, tab sis nws cov cua sov tsis zoo cuam tshuam rau nws txoj kev siv cov khoom siv raw rau cable rwb thaiv tsev. Vim tias qhov tsis muaj zog ntawm kev sib cuam tshuam hauv cheeb tsam amorphous, qhov kub ntawm cov polyethylene feem ntau yog li 140 degree, thiab nws cov neeg kho tshuab lub zog yuav txo qis heev thaum mus txog qhov melting point ntawm polyethylene, thiab cov cracking kuj deteriorates.
Thaum linear macromolecular chains yog tshuaj los yog lub cev ua tiav, cov txheej txheem ntawm kev koom ua ke hauv daim ntawv sib txuas sib txuas hu ua crosslinking lossis "vulcanization". Crosslinked polyethylene muaj cov yam ntxwv ntawm mesh hom thiab lub cev qauv, thiab nws cov cua sov kuj yuav txhim kho nrog kev nce ntawm crosslinking, thiab cov txheeb ze thermal elongation yuav txo raws li. Vim nws qhov kev txhim kho tseem ceeb hauv cov khoom siv hluav taws xob thiab cov cua sov, nws tau dhau los ua cov khoom siv hluav taws xob siv hluav taws xob dav dav.
Cov txheej txheem ntawm crosslinking polyethylene los ntawm crosslinking los tsim cross-linked polyethylene yog muab faib ua ob pawg: chemical method thiab lub cev txoj kev, thiab cov txheej txheem kev paub nyob rau hauv kev lag luam feem ntau suav nrog cov nram qab no tsib: high-zog irradiation crosslinking, silane crosslinking, peroxide crosslinking. , ultraviolet crosslinking, thiab ntsev crosslinking. Ntawm lawv, peroxide crosslinking txoj kev (tseem hu ua chemical crosslinking) yog ib txoj kev sib txuas sib txuas tsim nyog rau kev tsim cov kab nruab nrab thiab qib high-voltage cables, thiab nws cov ntsiab lus yog cov tshuaj dawb radical tshwm sim los ntawm qhov kub thiab txias decomposition ntawm peroxide. , thiab tom qab ntawd PE yog sib txuas. Peroxides yog decomposed los ntawm tshav kub los tsim dawb radicals, thiab cov txheej txheem ntawm crosslinking cov tshuaj tiv thaiv yog raws li nram no:
Txoj kev sib txuas
Muaj ob hom kev sib txuas sib txuas rau polyethylene: lub cev crosslinking (radiation crosslinking) thiab chemical crosslinking. Chemical crosslinking muab faib ua silane crosslinking thiab peroxide crosslinking.
Lub cev crosslinking
Radiation crosslinking: cov khoom siv polyethylene, xws li polyethylene sheaths, films, nyias-walled hlab, thiab lwm yam khoom coated ntawm cov hlau, yog crosslinked nrog-rays thiab high-zog rays (ua rau polyethylene macromolecules los tsim dawb radicals thiab daim ntawv CC crosslinked chains) . Lub degree ntawm crosslinking yog cuam tshuam los ntawm cov tshuaj tua hluav taws xob thiab qhov kub thiab txias, thiab qhov crosslinking point nce nrog qhov nce ntawm cov hluav taws xob sib txuas, yog li los ntawm kev tswj cov hluav taws xob hluav taws xob, cov khoom sib txuas ntawm polyethylene nrog qee qhov kev sib txuas tuaj yeem tau txais.
Hla-txuas polyethylene tsim los ntawm hluav taws xob crosslinking txoj kev muaj cov hauv qab no zoo: crosslinking thiab extrusion yog nqa tawm nyias, cov khoom zoo yog yooj yim los tswj, ntau lawm efficiency yog siab, thiab cov seem seem yog tsawg; Tsis muaj lwm yam dawb radical pib (xws li peroxides, thiab lwm yam) yuav tsum tau thaum lub sij hawm crosslinking txheej txheem, uas tswj kev huv ntawm cov khoom thiab txhim kho cov khoom hluav taws xob ntawm cov khoom; Nws yog tshwj xeeb tshaj yog haum rau me me-section, nyias-walled insulated cables uas nyuaj rau tsim los ntawm cov tshuaj crosslinking. Txawm li cas los xij, hluav taws xob crosslinking kuj muaj qee qhov tsis zoo, xws li qhov yuav tsum tau ua kom lub zog nrawm ntawm cov kab hluav taws xob thaum hla cov ntaub ntawv tuab; Rau kev sib txuas ntawm cov khoom puag ncig xws li cov xov hlau thiab cov cables, nws yog ib qho tsim nyog los tig lawv los yog siv ob peb kab hluav taws xob los ua kom cov irradiation sib xws; Kev nqis peev ib zaug yog ntau heev; Kev ua haujlwm thiab kev siv thev naus laus zis yog qhov nyuaj, thiab cov teeb meem kev tiv thaiv kev nyab xeeb hauv kev ua haujlwm kuj tseem hnyav heev.
Chemical cross-linking
Chemical crosslinking yog siv cov tshuaj crosslinking cov neeg ua haujlwm rau crosslink polymers, hloov los ntawm cov qauv linear mus rau lub network qauv.
Kev xaiv ntawm tus neeg sawv cev crosslinking yuav tsum nyob ntawm ntau yam polymer, kev siv thev naus laus zis, thiab kev ua haujlwm ntawm cov khoom lag luam, tus neeg sawv cev crosslinking zoo tagnrho ntxiv rau kev ua tau raws li qee qhov kev cai tshwj xeeb yuav tsum muaj cov hauv qab no cov cai: siab crosslinking tus nqi, ruaj khov crosslinking qauv; loj ua kev nyab xeeb, yooj yim rau siv, nruab nrab siv tau lub sij hawm tom qab ntxiv resin, tsis muaj ntxov ntxov los yog lig dhau lawm crosslinking drawbacks; tsis cuam tshuam rau kev ua haujlwm thiab kev siv cov khoom siv; non-toxic, non-polluting, tsis ua rau tawv nqaij thiab qhov muag.
Hauv kev sib txuas tshuaj lom neeg, muaj peroxide crosslinking, silane crosslinking, thiab azo crosslinking:
(1) Peroxide crosslinking thiab crosslinking tus neeg sawv cevPeroxide crosslinking, feem ntau siv cov organic peroxide ua tus neeg sawv cev crosslinking, nyob rau hauv qhov kev txiav txim ntawm tshav kub, decomposes los tsim cov dawb radicals, uas ua rau cov polymer carbon saw tsim cov ntsiab lus tseem ceeb thiab tsim cov pa roj carbon monoxide crosslinking los ua ib qho network qauv. Cov cuab yeej no yuav tsum muaj cov cuab yeej siv high-pressure extrusion kom cov tshuaj tiv thaiv crosslinking yog nqa tawm nyob rau hauv lub thoob, thiab tom qab ntawd cov khoom yog rhuab siv cov cua kub ceev, uas ua rau cov khoom sib txuas. Yog li ntawd, kev siv cov peroxide crosslinking txoj kev los tsim cov yeeb nkab polyethylene tsis yooj yim rau kev tswj, cov khoom zoo tsis ruaj khov, thiab kev ua haujlwm tas mus li nyuaj dua.
(2) Azo crosslinking
Cov txheej txheem yog muab cov azo compound rau hauv PE thiab extrude ntawm qhov kub qis dua azo compound decomposition, thiab extrusion yog decomposed los ntawm high-temperature ntsev da dej, thiab cov azo compound yog decomposed los tsim dawb radicals, pib polyethylene crosslinking. Nws feem ntau yog siv rau cypress cov pos hniav cov ntaub ntawv uas tsis tshua muaj melting kub thiab muaj ob peb lub tswv yim siv rau yas.
(3) Silane crosslinking thiab crosslinking tus neeg sawv cev
Nyob rau hauv lub sixties ntawm lub xyoo pua nees nkaum, silane crosslinking tshuab tau ntse tsim. Cov thev naus laus zis siv cov yas silanes uas muaj ob daim ntawv cog lus kom hnov mob polymers nyob rau hauv qhov kev txiav txim ntawm cov neeg pib tsim silane-grafted polymers, uas yog hydrolyzed nyob rau hauv dej nyob rau hauv lub xub ntiag ntawm silanol condensation catalyst los tsim ib tug networked oxane saw crosslinked qauv. Silane crosslinking thev naus laus zis tau txhawb nqa ntau lawm thiab siv cov khoom sib txuas ntawm polyethylene vim nws cov cuab yeej siv yooj yim, kev tswj tau yooj yim, kev nqis peev tsawg, qib siab ntawm crosslinking ntawm cov khoom tiav, thiab cov khoom zoo. Ntxiv rau polyethylene thiab silane, catalysts, pib, antioxidants, thiab lwm yam kuj tseem siv rau hauv kev sib txuas.
Piv nrog rau lwm txoj hauv kev, cov khoom siv polyethylene tau los ntawm silane crosslinking muaj qhov zoo hauv qab no:
(1) Cov cuab yeej siv tsawg dua, kev tsim khoom siab, thiab tus nqi qis.
(2) Cov txheej txheem yog ntau yam, haum rau txhua qhov ntom ntom polyethylene, thiab kuj haum rau feem ntau polyethylene nrog muab tub lim.
(3) Tsis txwv los ntawm thickness.
(4) Tus nqi ntawm peroxide yog me me (tsuas yog 10% thaum peroxide yog crosslinked ib leeg), yog li tsawg dua micropores tsim nyob rau hauv polyethylene rwb thaiv tsev txheej, uas yog tsim nyog los tswj lub siab rwb thaiv tsev ntawm polyethylene.
Cov ntawv thov tseem ceeb
Vim nws cov khoom zoo heev, cross-linked polyethylene yog siv los ua high-voltage, high-frequency, tshav kub-resistant rwb thaiv tsev ntaub ntawv thiab hlau thiab cable claddings xav tau los ntawm rockets, missiles, motors, transformers, thiab lwm yam. Thaum tshav kub kub-shrinkable films, ntau yam cua sov-resistant kav, ua npuas ncauj yas, corrosion-resistant chemical khoom linings, Cheebtsam thiab ntim, tsim cov nplaim retardant tsev cov ntaub ntawv, thiab lwm yam. Tam sim no, qhov loj tshaj plaws ntawm kev siv yog cov hlau thiab cable, yeeb nkab, thiab ua npuas ncauj.
1. Hla-txuas polyethylene cable khoom
Lub tshav kub tsis kam ntawm lub cable nrog cross-linked polyethylene raws li rwb thaiv tsev yog siab dua li ntawm polyvinyl chloride, nws yuav siv tau rau lub sij hawm ntev ntawm 90 degree, thiab lub tshav kub kuj kub nyob rau hauv luv luv Circuit Court tuaj yeem ncav cuag 250 degree; Lub rwb thaiv tsev tsis kam yog siab, lub dielectric poob tangent yog me me, thiab nws yeej tsis hloov nrog kev hloov ntawm kub; Nws muaj zoo hnav tsis kam thiab ib puag ncig kev ntxhov siab tawg. Thaum sib txuas polyethylene raug hlawv los ntawm cables, carbon dioxide thiab dej raug tsim, thaum PVC cables tsim hydrogen chloride teeb meem gases thaum hlawv; Tsis tas li ntawd, qhov ceev ntawm cross-linked polyethylene yog kwv yees li 40% me dua li ntawm PVC, uas tuaj yeem txo qhov zoo ntawm cov nyiaj siv ua haujlwm.
2. Hla-txuas polyethylene yeeb nkab
Cov yeeb nkab uas tsim los ntawm kev sib txuas ntawm polyethylene muaj qhov zoo ntawm kev nkag siab ntawm lub zog, kev tiv thaiv corrosion, lub teeb yuag, thiab kev ua haujlwm kub zoo. Aluminium-yas composite yeeb nkab uas siv cov ntoo khaub lig-txuas polyethylene muaj zog cua nruj thiab siab tawg tsis kam. Nws muaj antistatic thiab shielding nyhuv.
Piv nrog rau cov yeeb nkab PVC thiab cov yeeb nkab polyethylene zoo tib yam, cov yeeb nkab sib txuas polyethylene tsis muaj cov yas yas, yuav tsis mildew thiab kab mob; Tsis muaj cov khoom xyaw tsim nyog, ua tau raws li FDA cov qauv, thiab tuaj yeem siv rau hauv cov kav dej haus; Cov cua kub zoo, zoo tib yam polyvinyl chloride thiab polyethylene yeeb nkab thaum tshav kub kub yog 60-75 degree, thaum cross-linked polyethylene yeeb nkab yog 90 degree, qhov siab tshaj plaws instantaneous kub tuaj yeem ncav cuag 185 degree, tuaj yeem tiv taus -75 degree qis; Kev khiav hauj lwm qhov kub thiab txias, tuaj yeem siv tau ntev hauv qab -75-95 degree, thiab lub neej kev pab cuam mus txog 50 xyoo. High cross-linking, siab ceev, zoo siab kuj; Tshuaj corrosion kuj zoo heev, thiab ib puag ncig kev nyuaj siab cracking kuj yog zoo heev, txawm nyob rau ntawm qhov kub thiab txias, nws yuav siv tau los thauj ntau yam tshuaj thiab kev nyuaj siab cov ntaub ntawv nrog ceev cov yeeb nkab, cross-linked polyethylene yeeb nkab yog lub teeb nyob rau hauv hnyav, tsuas yog hais txog 1. / 8 ntawm cov yeeb nkab hlau; Zoo corrosion kuj thiab hnav tsis kam. Tus nqi hnav tsawg dua 1/4 ntawm cov yeeb nkab steel, thiab lub neej kev pab cuam yog 2-6 npaug ntawm cov yeeb nkab steel; Cov phab ntsa sab hauv yog du, cov kua dej tsis kam yog me me, thiab ntawm tib lub yeeb nkab txoj kab uas hla, qhov kev xa tawm yog loj dua li ntawm cov yeeb nkab hlau, thiab lub suab nrov qis dua; Kev sib kis tau zoo, thiab qhov sib kis ntawm cov kua tau nce 30% -40% piv nrog cov yeeb nkab steel; Cov thermal conductivity tsawg dua li cov kav hlau hlau, yog li nws cov thermal rwb thaiv tsev kev ua tau zoo heev. Thaum siv rau hauv cov cua sov, tsis tas yuav txuag hluav taws xob, thiab cov cua sov poob yog me me; Nws tuaj yeem khoov tau arbitrarily thiab yuav tsis nkig thiab tawg; Hluav taws xob rwb thaiv tsev kev ua tau zoo, kev teeb tsa yooj yim, thiab kev teeb tsa ua haujlwm tsawg dua li ib nrab ntawm cov yeeb nkab hlau, tus nqi qis qis.
Vim yog cov khoom siv zoo heev ntawm kev sib txuas ntawm cov yeeb nkab polyethylene. Nrog rau kev tu cev tsis muaj tshuaj lom, nws tau raug suav tias yog lub cim tshiab ntawm cov kav dej ntsuab, feem ntau yog siv rau hauv cov hauv qab no:
(1) Cov dej txias thiab dej kub thiab cov kav dej haus rau cov tsev;
(2) Chilled dej system rau lub tsev cua txias;
(3) Cov cua sov hauv tsev;
(4) Cov cua sov hauv av;
(5) Cov kav dej ntawm lub tshuab rhaub dej hauv tsev;
(6) Kev thauj mus los rau cov dej haus, cawv, mis nyuj, thiab lwm yam dej hauv kev lag luam zaub mov;
(7) Kev lag luam tshuaj lom neeg thiab roj av kev thauj mus los kav dej;
(8) Lub tshuab tub yees thiab dej kho qhov kav dej.
(5) Kev laus ua haujlwm zoo thiab ua haujlwm ntev.
